Clarify opportunity notification copy

[Pigbibi]

Summary

• rewrite opportunity review cards to explain why the signal matters in plain language
• add concrete suggested checks for VIX, price rebound persistence, strategy exposure, and risk-control state
• keep internal route/veto/governance fields out of user-facing notification copy

Verification

• timeout 120s env PYTHONPATH=/home/ubuntu/Projects/QuantStrategyPlugins/src uv run --no-project --with pandas --with pytest pytest -q
• timeout 120s uv run --no-project --with ruff ruff check .